Centralizer

ABSTRACT

A centralizer for a pipe or other elongate member is formed from a plurality of tubular bodies ( 16 ) each having a through passage ( 23 ) that is connected end-to-end to form a continuous passageway. Each of the tubular bodies ( 16 ) has a female connector portion ( 26 ) at one end and a male connector portion ( 24 ) at the opposite end that fits into the female connector portion ( 26 ) with longitudinal and/or angular play. The securing means in the form of a mounting flange ( 14 ) is also provided to fix the centralizer with respect to a J-tube through which the centralizer is to pass. The invention centralizes the elongate member in the J-tube and maintains the allowable minimum bending radius, whilst eliminating, or reducing to acceptable levels, the contact loads and abrasion on the elongate member.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of British Patent Application No. 05 16041.1, filed on Aug. 4, 2005, which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to centralizers and in particular, but not exclusively, to centralizers for use with underwater elongate members such as umbilicals, pipes, risers and the like.

2. Background Art

In sub-sea applications, particularly in the oil and gas production industry, it is often necessary to secure an elongate member such as a pipe or umbilical to a production platform, surface vessel or the like. This is conventionally achieved by passing the elongate member through a so-called “J-tube” which is a downwardly-projecting tube secured to the production platform, surface vessel or the like. The elongate member is then secured in position.

The internal diameter of the J-tube is generally somewhat larger than the elongate member that passes through it. In some circumstances, the J-tube is designed to be curved. In such situations, since the elongate member is generally of limited flexibility, it is not possible for it to follow the curve of the J-tube precisely and as a consequence it tends to contact the internal wall of the J-tube at a relatively small number of separated points rather than having a continuous contact with the J-tube.

This results in abrasion of the elongate member at the contact points, which will therefore require repair or replacement, which is a costly and time-consuming exercise.

SUMMARY OF THE INVENTION

It is therefore an aim of the present invention to centralize the elongate member in the J-tube and maintain the allowable minimum bending radius, whilst eliminating, or reducing to acceptable levels, the contact loads and abrasion.

In accordance with the present invention, there is provided a centralizer for an elongate member, comprising a plurality of tubular bodies each having a through passage, the tubular bodies being connected end-to-end to form a continuous passageway, each tubular body comprising connection means for connecting to an adjacent tubular body while permitting longitudinal and/or angular play between adjacent tubular bodies, and securing means for securing the centralizer with respect to an elongate tubular member through which the connected tubular bodies to pass.

If such an arrangement is located in a curved J-tube, it centralizes the elongate member in the J-tube and maintains the allowable minimum bending radius. It also eliminates, or reduces to acceptable levels, the contact loads and abrasion of the elongate member.

Preferably the connection means comprises a female connector portion at one end and a male connector portion at the opposite end adapted to fit into the female connector portion of an adjacent tubular body.

In one embodiment the female connector portion comprises a socket or recess having an aperture defined by an inturned peripheral lip.

Preferably, the male connector portion comprises a projecting rib whose outer diameter exceeds the inner diameter of the inturned peripheral lip.

Preferably, the longitudinal length of the socket or recess exceeds the longitudinal length of the projecting rib of the male connector portion.

Preferably, the internal diameter of the socket or recess exceeds the external diameter of the projecting rib of the male connector portion.

Advantageously, each of the said tubular bodies comprises a plurality of portions and means for securing the portions together to form the tubular body.

Preferably, the portions of the tubular body are substantially identical.

In one embodiment, each of the tubular bodies comprises two parts.

Preferably, the centralizer comprises a plurality of substantially identical tubular bodies.

Preferably, the securing means comprises means for securing to one of the said tubular bodies.

In one embodiment, the securing means comprises a flange and means for attaching the flange to the tubular bodies.

BRIEF DESCRIPTION OF THE DRAWINGS

By way of example only, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings, in which:

FIG. 1 is a side view of an embodiment of centralizer in accordance with the present invention;

FIG. 2 is an end view of the centralizer illustrated in FIG. 1;

FIGS. 3 a and 3 b are perspective views of a first one of the components, and of a portion of that component, respectively, of the centralizer of FIG. 1;

FIGS. 4 a and 4 b are perspective views of another of the components, and of a portion of that component, respectively, of the centralizer of FIG. 1; and

FIG. 5 is a cross-sectional view of the centralizer of FIG. 1, showing it installed on a curved J-tube.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIGS. 1 to 4, the centralizer 10 comprises a hollow elongate sheath 12 and a securing flange 14. In one embodiment, the hollow elongate sheath 12 comprises five identical interconnected tubular centralising sleeves 16 and an end sleeve 18, all formed from a polyurethane elastomer. Each of the cylindrical sleeves 16 is generally cylindrical and is formed from two identical half-sleeves 16 a as illustrated in FIG. 3, the two halves being secured together to form a tubular sleeve by means of six bolts 20 which pass through aligned apertures 22 in the sleeve halves, to define a cylindrical passage 23.

One end of each cylindrical sleeve 16 is provided with a male connector portion in the form of an upstanding peripheral lip 24, the opposite end being provided with a female connector portion formed by an internal peripheral annular recess 26 which is defined by an inturned overhanging peripheral lip 28 at the opposite end. The internal diameter of the peripheral recess 26 is slightly larger than the external diameter of the peripheral lip 24 at the opposite end and the longitudinal length of the lip 24 is slightly shorter than the longitudinal length of the peripheral recess 26. In addition, the end face 30 of the sleeve adjacent to the peripheral lip is, in one embodiment, inclined towards the opposite end by approximately 1.5°, although this angle can be changed to suit the particular circumstances such as the required bend radius.

As a result, the peripheral lip 24 of each of the sleeves 16 can be received and retained in the internal peripheral recess 26 of another of the sleeves, but the relative dimensions of the peripheral rib and peripheral recess allow annular and longitudinal play of the two sleeves with respect to one another, as illustrated in FIG. 5.

The inner end of the end sleeve 18 is identical to the inner end of the sleeve portion 16, in that it has an identical internal peripheral recess 26. However, the outer end of the end sleeve 18 is shaped into a frusto-conical wall 29 and does not have an upstanding peripheral lip, in contrast to the other centralising sleeves 16.

In use, the first sleeve 16 is fitted over a mounting flange 32 of the securing plate. The other centralising flanges 16 are then secured successively, with the peripheral rim 24 of each preceding centralising sleeve being received in the internal peripheral recess 26 of the next securing sleeve 16. When all the sleeves 16 have been secured in position, the end sleeve is secured to the outermost sleeve 16, with the peripheral rim 24 of the final sleeve 16 being received in the internal peripheral recess 26 of the end sleeve 18. The centralizer 10 is then attached to the securing flange of a J-tube 36 (FIG. 5) by means of bolts passing through each of sixteen equally-spaced apertures 15 in the securing flange 14, which are aligned with corresponding holes in the securing flange of the J-tube.

As best seen in FIG. 5, when the centralizing arrangement is assembled, a continuous through passage is formed by the cylindrical passages 23 of the sleeves 16, 18. Each sleeve 16, 18 can pivot slightly with respect to the sleeve or sleeves to which it is connected. As a consequence, the passageway of the centralizer 10 changes direction stepwise gradually. As shown in FIG. 5, this allows the centralizer to follow the contours of a curved J-tube 36 while providing a continuous centralized passageway through which a pipe, umbilical or other elongate member can pass.

The invention is not restricted to the details of the foregoing embodiment. For example, the sleeves can be made from a material different from that described, or from more than one material.

While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. 

1. A centralizer for an elongate member, comprising a plurality of tubular bodies each having a through passage, tubular bodies in the plurality being connected end-to-end to form a continuous passageway, each tubular body comprising connection means for connecting to an adjacent tubular body while permitting play between adjacent tubular bodies that is at least one of longitudinal and angular play, and securing means for securing the centralizer with respect to an elongate tubular member through which the connected tubular bodies pass.
 2. A centralizer as claimed in claim 1, wherein the connection means comprises a female connector portion at one end and a male connector portion at an opposite end of a tubular body, the connection means being adapted to fit into the female connector portion of an adjacent tubular body.
 3. A centralizer as claimed in claim 2, wherein the female connector portion comprises a recess having an aperture defined by an inturned peripheral lip.
 4. A centralizer as claimed in claim 3, wherein the male connector portion comprises a projecting rib whose outer diameter exceeds the inner diameter of the inturned peripheral lip.
 5. A centralizer as claimed in claim 4, wherein a longitudinal length of the recess exceeds a longitudinal length of the projecting rib of the male connector portion.
 6. A centralizer as claimed in claim 4, wherein an internal diameter of the recess exceeds an external diameter of the projecting rib of the male connector portion.
 7. A centralizer as claimed in claim 1, wherein each of the plurality of tubular bodies comprises a plurality of portions and means for securing the portions together to form the tubular body.
 8. A centralizer as claimed in claim 7, wherein the portions of a tubular body are substantially identical.
 9. A centralizer as claimed in claim 1, wherein each of the tubular bodies comprises two parts.
 10. A centralizer as claimed in claim 1, wherein the plurality of tubular bodies comprise substantially identical tubular bodies.
 11. A centralizer as claimed in claim 1, wherein the securing means comprises means for securing a flange to one of the tubular bodies.
 12. A centralizer as claimed in claim 1, wherein the securing means comprises a flange and means for attaching the flange to one of the plurality of tubular bodies. 